The present invention relates generally to devices useful for improving the operator's skills in manipulating steerable catheters and scopes. In particular, the invention describes a device for assessing colonoscope manipulation and maneuvering. The invention allows simultaneous measuring and display of colonoscope insertion forces and torques, linear and rotational accelerations of the colonoscope shaft, real time images of the colon, and patient's pain level throughout the procedure.
In many cases, it has been desirable to examine internal organs, passages and the like of the human body for purposes of diagnosis, biopsy, and therapeutic interventions. One method of examining the internal organs of the patient without major surgery is to insert a remote sensing device such as an endoscope into the body through a natural body orifice such as a colon or a specially-prepared surgical opening.
Although the preferred application of the invention is for use with a colonoscope, other devices can also be coupled to the device disclosed herein. Therefore, the word “colonoscope” is used throughout this description to broadly include various types of direct vision and fiber optic endoscopes, fiberscopes, arthoscopes, laparoscopes, and other types or steerable and deflectable catheters and tubes designed to be inserted into tight openings and curved passages.
The use of steerable scopes for internal examination is not limited to medicine. Remote sensing devices can be used to examine the interior of otherwise inaccessible mechanical structures without opening them, such as aircraft wings, the walls of buildings, and the enclosed areas of any structure. In these cases, an internal examination without putting a major opening in the structure can help to determine the reason for mechanical failure or the level of corrosion levels.
The preferred area of interest for the device of the present invention is in medicine, and more particularly in colonoscopy. Colonoscopy is the preferred method to screen for colorectal cancer, a disease that affects 150 thousand patients per year in the US. Several million screening, diagnostic and therapeutic colonoscopies are performed each year in the U.S. hospitals and ambulatory surgery centers. Colonoscopy requires a physician to inspect the colonic mucosal surface by applying force to a colonoscope and advancing this flexible tube through a series of stationary and movable colonic loops.
When using a colonoscope, a common problem is to be able to maneuver the inspection end of the scope and position it in proximity to the area of interest. This maneuvering is performed by a trained operator who uses a combination of visual assessment of images obtained by colonoscope and tactile coordination to advance the shaft of the colonoscope through the twists and turns of the colon. The operator subjectively senses the resistance to maneuvers by the “feel” of the instrument and anticipates the amount of force necessary to advance the device forward. The application of force to the colon and its anatomic structures can be painful for the patient. Particularly undesirable is the frequent occurrence of excessive contact pressure on an internal tissue, which can result in perforation. Sedation with analgesia is frequently required to make the procedure comfortable for the patient. Preliminary studies suggest that there is significant variation in forces applied by different operators and that these forces can be excessive. Operator training programs are designed to reduce the variation in technique, however training metrics remain subjective and the characterization of effective, less forceful insertion methods is not yet available. The need therefore exists to provide a device allowing an effective, low-cost method to define the best practices and to implement these practices as part of training, ongoing education and quality assurance.
There is an extensive array of surgical instruments, catheters and endoscopes that can be introduced and guided into and through both solid and hollow organ systems such as gastrointestinal tract, blood vessels and heart, urologic and gynecologic systems. These devices are designed to perform a variety of functions such as illumination, introduction of radiographic contrast materials and other fluids, surgical therapies, dilatation, etc.
Examples of such guiding or steering techniques and systems for catheters are found in U.S. Pat. No. 4,983,165 to Loiterman entitled “Guidance System For Vascular Catheter Or The Like,” U.S. Pat. No. 4,776,844 to Ueda entitled “Medical Tube,” U.S. Pat. No. 4,934,340 to Ebling et al. entitled “Device For Guiding Medical Catheters and Scopes,” U.S. Pat. No. 4,930,521 to Metzget et al. entitled “Variable Stiffness Esophageal Catheter,” U.S. Pat. No. 3,470 to Barchilon entitled “Dirigible Catheter,” U.S. Pat. No. 3,605,725 to Bentov entitled “Controlled Motion Devices,” and the PCT patent application Ser. No. WO88/00810 of Tenerz et al. entitled “Guide For Mechanical Guiding Of A Catheter In Connection With Cardio And Vessel Examination.” These catheters, however, fail to give the operator sufficient control of the distal end of the catheter and make it difficult to manipulate the distal end for specific isolation of particular sections of the body vessel or cavity.
Other steerable catheters or systems have been made to try to give the physician control of the use of the catheter during surgical procedures. Fluids and various mechanisms are employed for controlling the direction of movement of the distal end of the catheter. Examples of these attempts are found in the PCT patent application Ser. No. WO91/11213 of Lundquist et al. entitled “Catheter Steering Mechanism,” European Patent Application No. 370,158 of Martin entitled “Catheter For Prolonged Access,” and U.S. Pat. No. 4,737,142 to Heckele entitled “Instrument for Examination and Treatment of Bodily Passages.” These devices, however, still fail to provide sufficient control and manipulation of the catheter needed for use with the surgical tools and fluids required for a procedure such as colonoscopy.
A handheld force measuring device to be used with the colonoscope tube is disclosed in U.S. Pat. No. 6,981,945 issued to Sarvazyan, et al. entitled “Colonoscope Handgrip with Force and Torque Monitor” incorporated herein in its entirety by reference. It describes a handgrip attachment for a colonoscope shaft capable of measuring and presenting to the operator of radial and longitudinal forces applied by the operator during the manipulation of the colonoscope. The handgrip includes a set of sensors such as strain gages positioned on all sides of a rectangular bar to measure the forces between the handgrip and the shaft of the colonoscope. The measurements are then transmitted to an electronic unit for data processing and then further to a display system such as a personal computer.
U.S. Pat. No. 5,881,321 to Kivolowitz, Mar. 9, 1999, discloses a system for using absolute position of a hand-held camera by use of inertial sensors incorporated into the structure of the camera to detect the movement of the camera along three orthogonal axes, as well as angular rotation around the three axes. U.S. Pat. No. 6,097,423 to Mattsson-Boze, et al., Aug. 1, 2000, discloses an endoscope and camera with which a display observed through the optics in the endoscope is rotated to a desired orientation using an accelerometer. The accelerometer generates a signal indicative of the local vertical and is used in the particular embodiment to rotate a CCD image sensor aligned with the optical axis of the endoscope so as to maintain a desired orientation of a display of the image on a monitor. U.S. Pat. No. 7,211,042 to Chatenever, et al., May 1, 2007 describes the endoscope video camera system with an inertial sensor to sense rotations of the received image about the optical axis of the endoscope and the sensor's output signals are used to rotate either the image or the image sensor. In case of rotation of the image sensor as the rotation sensor can be used a gyroscope or a pair of accelerometers. These inventions are related to a re-orientation of an image as viewed on a display screen to present the image in a preferred relationship to the viewer's reference frame. Proposed solutions however do not allow using visual data for evaluation of endoscope motion.
A more advanced version of that device is shown in our co-pending U.S. patent application Ser. No. 12/558,737 filed on Sep. 14, 2009 and entitled “A handgrip for Assessment of Colonoscope Manipulation” incorporated herein in its entirety by reference. This device includes force and torque sensors as well as linear and rotational acceleration sensors. This combination of sensors allows detecting not only the input forces and torques applied to the colonoscope shaft but also the resulting movement of the shaft in or out of the patient. Obstacles or obstructions to the advancement of the instrument are detected when sufficient force is not accompanied by expected advancement of the shaft.
Still, characterization of the movement of the shaft is only one part of the comprehensive characterization of the colonoscopy procedure. The second part is the patient and the level of discomfort or pain caused by manipulation of the shaft. The third and final part of this characterization is the final result of colonoscopy, namely the image of the specific parts of the colon provided by the scope.
The need exists for a comprehensive system that can tie together these three parts of the colonoscopy procedure, namely the manipulation of the colono scope shaft, level of patient's pain and discomfort as well as the image of the colon.